1. Field of the Invention
The present invention relates to a power operating apparatus for a vehicle door moveable between a closed position and an opened position, and specifically to a power operating apparatus suitable for an electrically powered, hinged back door.
2. Description of the Prior Art
As is generally known, a van, a wagon, or the like has usually a comparatively large hinged back door, a comparatively large hinged rear gate, or a comparatively large hinged tail gate, to form a wide door opening at the rear of the vehicle. Such a hinged back door (or a hinged rear gate or a hinged tail gate) can be opened upwards by way of upward pivotal movement about door hinges or closed downwards by way of downward pivotal movement about the door hinges. For the purpose of laborsaving, it is generally known to provide an electrically-driven vehicle door for a van or a wagon, in which the door is opened and closed by operation of a drive mechanism having a reversible electric motor. Such electrically-driven vehicle doors have been disclosed in Japanese Utility-Model Provisional Publication No. 5-52165 (already registered on Oct. 17, 1997 as a registration No. 2561335) and Japanese Utility-Model Provisional Publication No. 6-71852. In the power operating apparatus disclosed in the Japanese Utility-Model Provisional Publication Nos. 5-52165 and 6-71852, the electric drive means (the motor drive mechanism) is provided at the inside of the vehicle. Power produced by the drive mechanism is transmitted through a power-transmission member (or a power-transmission linkage) to a back door, so as to open or close the back door. In the Japanese Utility-Model Provisional Publication No. 5-52165, a cable (or a wire) is used as a power-transmission member. On the other hand, in the Japanese Utility-Model Provisional Publication No. 6-71852, a linkage, composed of a rod and an arm member, is used as a power-transmission member. In the prior-art vehicle door operating apparatus disclosed in the Japanese Utility-Model Provisional Publication Nos. 5-52165 and 6-71852, the power-transmission members, that is, the force-transmission cable and the power-transmission linkage (composed of a rod and an arm member) are commonly arranged along the inside of an inner peripheral edge of the door opening for the back door. The vehicle-door opening serves as a useful space for cargo work (a loading-and-unloading space). The wider an opening area of the door opening, the higher a work efficiency. However, in the previously-described prior-art vehicle door operating apparatus, the power-transmission member or the power-transmission linkage is arranged along the inside body panel (the body-panel inside wall) and along the inside of the inner peripheral edge of the door opening so that part of the luggage space (or baggage space) is occupied by the power-transmission member. As a result of this, the effective door-opening area is reduced undesiredly, thus lowering the work efficiency during loading and unloading through the door opening.
Accordingly, it is an object of the invention to provide a power operating apparatus for a vehicle door, which avoids the aforementioned disadvantages of the prior art.
It is another object of the invention to provide a convenient, compact power operating apparatus for a vehicle door, which is capable of reducing the burden of opening and closing the vehicle door by power movement of the vehicle door, and of realizing easy loading and unloading through a door opening having as wide an effective door-opening area as possible and of enhancing a work efficiency by a drive-mechanism plus power-transmission mechanism compactly mounted on the inside of the body panel.
In order to accomplish the aforementioned and other objects of the present invention, a power operating apparatus for a vehicle door moveable between an opened position and a closed position comprises a drive mechanism provided at an inside of a vehicle body with respect to a door opening of the vehicle door to power move the vehicle door in an opening direction toward the opened position and in a closing direction toward the closed position, a power-transmission mechanism mechanically linking the drive mechanism with the vehicle door to enable power transmission between the drive mechanism and the vehicle door, means for defining a through-opening in a body panel of the vehicle body so that the through-opening is arranged outside of an inner peripheral edge of the door opening, and the power-transmission mechanism having at least a linkage portion capable of going into and out of an interior of the vehicle body, wherein the linkage portion of the power-transmission mechanism is inserted into the through-opening, so that a locus of power movement of the linkage portion of said power-transmission mechanism is generated outside of the inner peripheral edge of the door opening. It is preferable that the linkage portion of the power-transmission mechanism is curved with a predetermined curvature in a longitudinal direction of the linkage portion, and contoured and dimensioned so that a centroid of the linkage portion, extending in the longitudinal direction, turns on a predetermined radius of curvature substantially corresponding to a distance between the centroid of the linkage portion and an axis of rotation for the vehicle door during power movement of the vehicle door. Preferably, a seal member may be provided along an inner periphery of the through-opening to prevent dust and moisture from entering the interior of the vehicle body through the through-opening. More preferably, a reinforcement may be provided along the inner periphery of the through-opening to partly enhance the rigidity of the body panel at and near the through-opening. The drive mechanism may have a slider disposed in the interior of the vehicle body and an electric motor initiating a reciprocating motion of the slider, and the power-transmission mechanism may have a link rotatably connected at one link end to the slider, and an arm rotatably connected at one arm end to another link end of the link and fixedly connected at another arm end to the vehicle door, and the arm substantially corresponds to the linkage portion of the power-transmission mechanism, capable of going into and out of the interior of the vehicle body. It is preferable that the drive mechanism is mounted on the inner peripheral wall of a roof panel of the vehicle body.
According to another aspect of the invention, a power operating apparatus for a hinged back door moveable between an opened position and a closed position comprises an electric drive mechanism provided at an inside of a vehicle body with respect to a door opening of the back door and including an electric motor selectively energizable to power move the back door in an opening direction toward the opened position and in a closing direction toward the closed position, a power-transmission mechanism mechanically linking the drive mechanism with the back door to enable power transmission between the drive mechanism and the back door, means for defining a through-opening in an inner body panel and an outer body panel of the vehicle body near the intersection between an upper roof rail portion and a rear pillar drip rail portion so that the through-opening is arranged outside of an inner peripheral edge of the door opening, and the power-transmission mechanism having at least a linkage portion capable of going into and out of an interior of the vehicle body, wherein the linkage portion of the power-transmission mechanism is inserted into the through-opening, so that a locus of power movement of the linkage portion of said power-transmission mechanism is generated outside of the inner peripheral edge of the door opening. It is preferable that the linkage portion of the power-transmission mechanism is curved with a predetermined curvature in a longitudinal direction of the linkage portion, and contoured and dimensioned so that a centroid of the linkage portion, extending in the longitudinal direction, turns on a predetermined radius of curvature substantially corresponding to a distance between the centroid of the linkage portion and an axis of rotation for the back door during power movement of the back door to minimize an opening area of the through-opening. Preferably, the through-opening may have an outwardly flanged portion slightly extending outwards from an inner periphery of the through-opening, and a seal member is fitted onto the outwardly flanged portion to prevent dust and moisture from entering the interior of the vehicle body through the through-opening. It is more preferable that a reinforcement is provided along an inner periphery of the through-opening to partly enhance the rigidity of the inner and outer body panels at and near the through-opening, and the inner body panel has an elliptical slot and the outer body panel has an elliptical slot, the reinforcement is formed as a substantially cylindrical reinforcement connecting the elliptical slot of the inner body panel with the elliptical slot of the outer body panel. The means for defining the through-opening may comprise the elliptical slot formed in the inner body panel, the elliptical slot formed in the outer body panel, and the substantially cylindrical reinforcement, and thus the substantially cylindrical reinforcement serves as a guide sleeve for the linkage portion of the power-transmission mechanism.